The status of a Test Instance as displayed in the Execution Grid has no inherent relation to the Assigned Cycle of that test instance.
Changing the Assigned Cycle does not automatically reset the status of test instances to No Run. If you want it to do that, you will need to customize the workflow code. Refer to the Administrator Guide for information on that topic.
By reassigning the folder to a new cycle, you lose the ability to report on the testing status of the previous cycle. A folder can be assigned to only one cycle at a time.
Assuming that you want to retain the ability to look at the relationship of test execution to previous cycles through the Management module, then the quickest way to get what you want is to copy the folder and assign the cycle to the new copy of the folder, as RajuThomas suggested.
Changing the Assigned Cycle does not automatically reset the status of test instances to No Run. If you want it to do that, you will need to customize the workflow code. Refer to the Administrator Guide for information on that topic.
By reassigning the folder to a new cycle, you lose the ability to report on the testing status of the previous cycle. A folder can be assigned to only one cycle at a time.
Assuming that you want to retain the ability to look at the relationship of test execution to previous cycles through the Management module, then the quickest way to get what you want is to copy the folder and assign the cycle to the new copy of the folder, as RajuThomas suggested.